Three Related Resonance Methods for the Determination of Sea Floor Geoacoustic Properties

A survey is presented of recent related work on the determination of seafloor geoacoustic properties using resonance methods. Three related techniques are discussed. The first two techniques have their common foundation in the Hankel transform inversion of complex pressure field versus range data to obtain a depth-dependent Green´s function versus horizontal wavenumber. In shallow water, the Green´s function shows resonances associated with the normal modes of the waveguide which are used to extract the geoacoustic properties (compressional and shear) as a function of depth into the bottom. The third technique has its basis in the fact that the plane-wave reflection coefficient of the ocean bottom shows resonances both as a function of frequency and angle of incidence. As in the Green´s function techniques, the resonances depend on the properties of the ocean bottom.